Baltimore-area gun stores say they have seen a spike in sales of assault-type rifles and other semiautomatic weapons since the Sandy Hook elementary school shootings in Connecticut and the subsequent talk by President Barack Obama, Gov. Martin O'Malley and other politicians of gun restrictions.

"Our numbers are even too high to give you a quote," said Jim Blucher, a salesman at Clyde's Sport Shop in Halethorpe. "Obama and O'Malley have become our best customers, politically."

Maryland State Police received 392 requests for background checks for gun buyers the day after the Newtown shootings — a significant increase over the previous Saturday. Statistics for this week were not available, and it was unclear whether the increased sales Dec. 15 were part of a broader trend.

Wilhelm Helfrich, owner of Duffy's Gun Room in Sparks, wonders about potential gun legislation in response to the Newtown, Conn., killings and how it might affect his business.

"I will end the year with my bills paid, but it's such an uncertain future in 2013," Helfrich said. "I'm deeply concerned."

On Dec. 14, police say, Adam Lanza, 20, armed with a semiautomatic, assault-type rifle, killed six adults and 20 Sandy Hook Elementary School students after shooting his mother to death — one of the worst mass shootings in U.S. history. Since then, many federal, state and municipal officials have called for tougher restrictions on gun sales.

Obama said Tuesday that he wants to revive the federal ban on assault-type weapons, which expired in 2004. O'Malley has reiterated his opposition to weapons like the semiautomatic rifle used in the Newtown shootings and said he will likely introduce a gun-control package in the coming legislative session.

Other Maryland officials have indicated that they will propose gun-control laws. Baltimore's Stephanie Rawlings-Blake was among several mayors in Maryland and across the nation who signed a letter urging Obama to tighten gun laws and make it easier to prosecute infractions.

At Clyde's, Blucher said gun enthusiasts are snapping up semiautomatic rifles, afraid that they might never have another chance to buy one. "It's a rush," he said.

The six to eight assault-type rifles typically hanging on the wall have been sold, and the store has had trouble restocking them because manufacturers and distributors say they're backlogged.

"There are people wondering if they'll be able to own certain things or purchase [semiautomatic weapons] before whatever they think will happen happens," said Duffy's manager John Walker.

In the past week, sales at the 30-year-old Sparks store have increased 100 percent to 200 percent over the same time last year, Walker said. Semiautomatic rifles have been the hot seller, with purchasers paying $1,200 to $5,000 for one of several models the store sells.

Semiautomatic pistols also are selling briskly. The store sold more than 20 Thursday, compared with three or four on an average day.

"You might get a little rush before Christmas," Walker said, "but this is definitely 10 times bigger than that."

Other states are also seeing increases.

The Denver Post reported that Colorado set a single-day record of 4,154 background-check submissions Dec. 14 for potential gun purchases, according to Colorado Bureau of Investigation officials.

The Seattle Times noted a similar rush as people lined up to apply for concealed-carry permits. On Dec. 17, people were standing 10-deep in the lobby at the King County sheriff's office, and clerks told some to come back another day.

The FBI did not have figures available on the number of background checks requested or processed for prospective gun buyers across the nation in December.

Some criminologists say that incidents such as the Newtown killings often spark gun sales, as more people seek protection.

"People become concerned that society is becoming more violent after the highly publicized mass shootings. As one response, they arm themselves," said Richard Rosenfeld, a professor at the University of Missouri-St. Louis and former president of the American Society of Criminology.

Maryland shop owners said they don't need statistics to tell them there's been a run on guns.

"We're certainly busier than we normally would be at this time," said Roy Bart, owner of Bart's Sports World in Glen Burnie. "We're getting a lot of phone calls and interest in handguns and assault rifles because that's what they think are going to be taken away."

Baltimore Sun reporter Jessica Anderson and the Reuters news service contributed to this article.